Coherent coupling of alkali vapor through random collisions.

Aklali vapor has long been a substantial tool in studying the atom-photon interactions in a well controlled environment, as well as the atom-atom interactions. The random spin-exchange collisions in warm alkali vapor are known to cause rapid decoherence, and act to equilibriate the spin state of the atoms. In this work we demonstrate experimentally that in contrast to the general concept of the collisions as a source of decoherence, a coherent coupling of one alkali specie (potassium) to another specie (rubidium) can be mediated by these random collisions.
Consequently, the potassium inherits the magnetic properties of the rubidium,
including its liftime (T1), coherence-time (T2), gyromagnetic ratio, and SERF magnetic field threshold. We further show that this coupling can be completely controlled by varing the strength of the magnetic field. Finally, we explain these phenomena analytically by modes-hybridization of the two species via spin-exchange collisions.